[niyas]

Dear All,

I am trying to use the flowRateInletVelocity BC. There is something that I can not understand: what does the `rho and rhoInlet' field mean?

The code looks like this:

inlet
{
type        flowRateInletVelocity;
flowRate  0.2;  
rho          rho;
rhoInlet   1.14      
value       uniform (0 0 0); // placeholder
}

If 'rho' is 'none', the flow rate is m3/s instead of kg/s.
If 'rho' is 'rho', then the density field name is 'rho'.
Please correct me if I am wrong.


If the density field cannot be found in the database, the user must
specify the inlet density using the 'rhoInlet' entry. Here what is meant by database? Anywhere in my case directory or '0 folder'?

Thank you.

[LuckyTran]

rho none; means the cased is incompressible
rho pineapple; means to look for and use the density field named pineapple


database means in memory at runtime. For the openfoam newbie this means a density field named pineapple in the 0 dir but it applies, at runtime, every timestep. OpenFOAM is highly customizable and you could even generate a density field on the fly using function objects in your controlDict. You don't have to start at 0 time. The pineapple density field needs to provide the value of rho at the inlet.

Many solvers calculate density from the EOS and therefore don't provide a value for density at startup. Hence the user must provide a value for the inlet density.

[niyas]

Thanks for the reply.

So, if I am using Gaseous Ethylene fuel at the inlet, then I should mention 'rhoInlet 1.153 kg/m3'.